U.S. patent application number 12/610699 was filed with the patent office on 2010-05-06 for ankle joint structure of walking assistance device.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. Invention is credited to Jun Ashihara, Yutaka Hiki, Yasushi Ikeuchi, Hiroshi Kudoh, Tatsuya Noda.
Application Number | 20100114332 12/610699 |
Document ID | / |
Family ID | 42132419 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100114332 |
Kind Code |
A1 |
Ashihara; Jun ; et
al. |
May 6, 2010 |
ANKLE JOINT STRUCTURE OF WALKING ASSISTANCE DEVICE
Abstract
An ankle joint structure of a walking assistance device is
capable of protecting a user from feeling uncomfortable by properly
following the foot motions of the user. An ankle joint has a turn
shaft member enabling a ground contact assembly to turn relative to
a leg link, a lateral rotation shaft member enabling the ground
contact assembly to laterally rotate relative to the leg link, and
a longitudinal rotation shaft member enabling the ground contact
assembly to longitudinally rotate relative to the leg link. The
turn shaft member is connected to the leg link, the longitudinal
rotation shaft member is connected to the ground contact assembly,
and the lateral rotation shaft member is disposed between the turn
shaft member and the longitudinal rotation shaft member.
Inventors: |
Ashihara; Jun; (Wako-shi,
JP) ; Noda; Tatsuya; (Wako-shi, JP) ; Kudoh;
Hiroshi; (Wako-shi, JP) ; Ikeuchi; Yasushi;
(Wako-shi, JP) ; Hiki; Yutaka; (Wako-shi,
JP) |
Correspondence
Address: |
RANKIN, HILL & CLARK LLP
38210 Glenn Avenue
WILLOUGHBY
OH
44094-7808
US
|
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
42132419 |
Appl. No.: |
12/610699 |
Filed: |
November 2, 2009 |
Current U.S.
Class: |
623/47 |
Current CPC
Class: |
A61H 2201/1635 20130101;
A61H 2201/1623 20130101; A61H 2201/1676 20130101; A61H 2201/1642
20130101; A61H 2201/165 20130101; A61H 2201/1215 20130101; A61H
3/008 20130101; A61H 2201/1633 20130101; A61H 3/00 20130101; A61F
5/0127 20130101; A61H 2201/1671 20130101; B25J 9/0006 20130101;
A61H 2201/5061 20130101; A61H 2201/5071 20130101; A61H 2201/1436
20130101 |
Class at
Publication: |
623/47 |
International
Class: |
A61F 2/66 20060101
A61F002/66 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 6, 2008 |
JP |
2008-285547 |
Claims
1. An ankle joint structure of a walking assistance device which is
used with a walking assistance device having a load transmit
assembly, a ground contact assembly, and a leg link provided
between the load transmit assembly and the ground contact assembly
to support at least a part of the weight of a user by the leg link
through the intermediary of the load transmit assembly, and which
connects the ground contact assembly and the leg link, the ankle
joint structure comprising: a turn shaft member that enables the
ground contact assembly to turn relative to the leg link; a
longitudinal rotation shaft member that enables the ground contact
assembly to rotate in a longitudinal direction relative to the leg
link; and a lateral rotation shaft member that enables the ground
contact assembly to rotate in a lateral direction relative to the
leg link, wherein the turn shaft member is disposed above or below
the longitudinal rotation shaft member and the lateral rotation
shaft member.
2. An ankle joint structure of a walking assistance device which is
used with a walking assistance device having a load transmit
assembly, a ground contact assembly, and a leg link provided
between the load transmit assembly and the ground contact assembly
to support at least a part of the weight of a user by the leg link
through the intermediary of the load transmit assembly, and which
connects the ground contact assembly and the leg link through toe
intermediary of a spherical joint, the ankle joint structure
comprising: a turn shaft member that enables the ground contact
assembly to turn relative to the leg link, wherein one end of the
turn shaft member is connected to one of the ground contact
assembly and the leg link, while the other end of the turn shaft
member swingably retains a sphere of the spherical joint, and a
joint shaft member provided on the sphere is connected to the other
of the ground contact assembly and the leg link.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ankle joint structure of
a walking assistance device which reduces load acting on a leg or
legs of a user, thereby assisting the user in walking.
[0003] 2. Description of the Related Art
[0004] Hitherto, there has been known a walking assistance device
which has a load transmit assembly, ground contact assemblies, and
leg links provided between the load transmit assembly and the
ground contact assemblies, and which supports at least a part of
the weight of a user by the leg links through the intermediary of
the load transmit assembly (refer to, for example, Japanese Patent
Application Laid-Open No. 2008-73506, which will be hereinafter
referred to as patent document 1).
[0005] Each of the ground contact assemblies and each of the leg
links of the walking assistance device disclosed in patent document
1 are connected by an ankle joint. The ankle joint includes a
lateral rotation shaft member, which enables toe ground contact
assembly to rotate in a lateral direction relative to the leg link,
a turn shaft member, which enables the ground contact assembly to
turn relative to the leg link, and a longitudinal rotation shaft
member, which enables the ground contact assembly to rotate in a
longitudinal direction relative to the leg link, these three shafts
being disposed in this order beginning at the top. Thus, the ankle
joint is constructed to have three degrees of freedom.
[0006] There has been known another ankle joint constructed to have
three degrees of freedom by connecting a ground contact assembly
and a leg link by a spherical joint (refer to, for example,
paragraph [0048] and FIG. 3 in Japanese Patent Application
Laid-Open No. 2007-54616, which will be hereinafter referred to as
patent document 2).
[0007] In the ankle joint disclosed in the aforesaid patent
document 1, as a user turns his/her foot, the longitudinal rotation
axial line of the longitudinal rotation shaft member and the
lateral rotation axial line of the lateral rotation shaft member
gradually approach a parallel state. Hence, in the state wherein
the user has turned his/her foot, if, for example, the user
attempts to rotate the foot in the longitudinal direction, then a
slight discrepancy may develop between a motion of the user's foot
and a motion of the ground contact assembly, causing the user to
feel uncomfortable.
[0008] According to the ankle joint disclosed in the aforesaid
patent document 2, limited operating angles due to the construction
of the spherical joint may lead to failure to properly respond to
foot motions of a user, making the user feel discomfort.
SUMMARY OF THE INVENTION
[0009] In view of the problems described above, an object of the
present invention is to provide an ankle joint structure of a
walking assistance device capable of properly following foot
motions of a user, thereby avoid making the user feel
uncomfortable.
[0010] To this end, a first aspect of the present invention
provides an ankle joint structure used with a walking assistance
device, which includes a load transmit assembly, a ground contact
assembly, and a leg link provided between the load transmit
assembly and the ground contact assembly to support at least a part
of the weight of a user by the leg link through the intermediary of
the load transmit assembly, the ankle joint structure connecting
the ground contact assembly and the leg link. The ankle joint
structure comprises a turn shaft member, which enables the ground
contact assembly to turn relative to the leg link, a longitudinal
rotation shaft member, which enables the ground contact assembly to
rotate in a longitudinal direction relative to the leg link, and a
lateral rotation shaft member, which enables the ground contact
assembly to rotate in a lateral direction relative to the leg link,
wherein the turn shaft member is disposed above or below the
longitudinal rotation shaft member and the lateral rotation shaft
member.
[0011] According to the first aspect of the present invention, the
turn shaft member is disposed above or below the longitudinal
rotation shaft member and the lateral rotation shaft member, so
that the longitudinal rotation shaft member and the lateral
rotation shaft member are connected without the intermediary of the
turn shaft member. Thus, unlike the conventional ankle joint
structures, when the ground contact assembly turns relative to the
leg link at the turn shaft member, the longitudinal rotation axial
line of the longitudinal rotation shaft member and the lateral
rotation axial line of the lateral rotation shaft member do not
approach the parallel state. This enables the ankle joint to
properly follow foot motions of a user, making it possible to
protect the user from feeling uncomfortable.
[0012] A second aspect of the present invention provides an ankle
joint structure used with a walking assistance device, which
includes a load transmit assembly, a ground contact assembly, and a
leg link provided between the load transmit assembly and the ground
contact assembly to support at least a part of the weight of a user
by the leg link through the intermediary of the load transmit
assembly, the ankle joint structure connecting the ground contact
assembly and the leg link through the intermediary of a spherical
joint. The ankle joint structure includes a turn shaft member,
which enables the ground contact assembly to turn relative to the
leg link, wherein one end of the turn shaft member is connected to
one of the ground contact assembly and the leg link, while the
other end of the turn shaft member swingably retains a sphere of
the spherical joint, and a joint shaft member provided on the
sphere is connected to the other of the ground contact assembly and
the leg link.
[0013] According to the second aspect of the present invention, the
provision of the turn shaft member permits a larger operating angle
in a turning direction with a larger rotational angle than that of
the longitudinal rotation shaft member and the lateral rotation
shaft member, and the spherical joint ensures a rotation with a
smaller rotational angle in the longitudinal direction and the
lateral direction than that of the turn shaft member. This allows
the motion of the ground contact assembly relative to a leg link to
properly follow a foot motion of the user.
[0014] In both first and second aspects of the present invent on,
the shaft which rotates an ankle to allow a foot of a user to turn
outward and inward in an upright posture state in which the walking
assistance device is standing with both ground contact assemblies
in contact with a ground surface of a floor surface or the like is
defined as a turn shaft, a shaft which rotates an ankle to move up
or down a tiptoe of a foot of the user in the upright posture state
is defined as the longitudinal rotation shaft, and a shaft which
rotates a foot of the user in the upright posture state in the
lateral direction, taking the ankle as a support point, is defined
as the lateral rotation shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a side view illustrating a first embodiment of an
ankle joint structure of a walking assistance device in accordance
with the present invention;
[0016] FIG. 2 is a front view of the walking assistance device of
the first embodiment;
[0017] FIG. 3 is a sectional view of the ankle joint structure of
the walking assistance device of the first embodiment taken at line
in FIG. 1;
[0018] FIG. 4 is a sectional view of the ankle joint structure of
the walking assistance device of the first embodiment taken at line
IV-IV in FIG. 2;
[0019] FIG. 5 is a side view illustrating a second embodiment of
the ankle joint structure of the walking assistance device in
accordance with the present invention;
[0020] FIG. 6 is a front view of the walking assistance device of
the second embodiment; and
[0021] FIG. 7 is a sectional view of the ankle joint structure of
the walking assistance device of the second embodiment taken at
line VII-VII in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The following will describe a walking assistance device of a
first embodiment to which an ankle joint structure in accordance
with the present invention has been applied, with reference to FIG.
1 to FIG. 3. As illustrated in FIG. 1 and FIG. 2, the walking
assistance device according to the first embodiment has a seating
member 1 serving as a load transmit assembly on which a user P sits
astride and a pair of right and left leg links 2 and 2 connected to
the seating member 1.
[0023] Each of the leg links 2 is constituted of a bendable link
having a first link member 4, which is connected to a hip joint 3
provided on the seating member 1, and a second link member 6, which
is connected to a lower end of the first link member 4 through a
rotary knee joint 5. Further, a ground contact member 8 (ground
contact assembly) to be attached to each of right and left feet of
the user P is connected to a lower end of the second link member 6
through ac ankle joint 7.
[0024] Each of the leg links 2 is further provided with a drive
source 9 for the knee joint 5. The knee joint 5 is rotationally
driven by the drive source 9 to drive each of the leg links 2 in a
stretching direction, that is, in the direction for pushing the
seating member 1 up, thereby generating a force for pushing the
seating member 1 up (hereinafter referred to as "the load support
force"). The Load support force generated in the leg link 2 is
transferred to the body trunk of the user P through the
intermediary of the seating assembly 1. More specifically, a part
of the weight of the user P is supported by the leg links 2 and 2
through the intermediary of the seating member 1 by the load
support force, thus reducing the load acting on the legs of the
user P.
[0025] The seating member 1 is composed of a saddle-shaped seat 1a,
on which the user P sits, a support frame 1b on a lower surface
supporting the seat 1a, and a hip pad 1c attached to a rising
portion at the rear end of the support frame 1b, which rises at the
rear of the seat 1a. The hip pad 1c is provided with an arcuate
handle 1d which can be grasped by the user P.
[0026] Further, the seating member 1 has an arcuate guide rail 3a
constituting the hip joint 3 for the leg links 2. The leg links 2
are movably engaged with the guide rail 3a through the intermediary
of a plurality of rollers 4b rotatably attached to a slider 4a
fixed on the upper end of the first link member 4. Thus, each of
the leg links 2 swings in the longitudinal direction about the
curvature center of the guide rail 3a. The supporting point of the
swing of each of the leg links 2 in the longitudinal direction
provides the curvature center of the guide rail 3a.
[0027] Further, the guide rail 3a is rotatably supported by a
rising portion of the rear end of the support frame 1b of the
seating member 1 through the intermediary of a longitudinal support
shaft 3b. Hence, the guide rail 3a is connected to the seating
member 1 such that the guide rail 3a may swing in the lateral
direction. This allows each of the leg links 2 to swing in the
lateral direction, enabling a leg of the user P to be abducted. The
curvature center of the guide rail 3a and the axial line of the
support shaft 3b are positioned above the seat 1a. This makes it
possible to prevent the seating member 1 from significantly tilting
vertically or laterally when the weight of the user P shifts.
[0028] The drive source 9 is constituted of an electric motor with
a speed reducer 9a mounted on the outer surface of an upper end
portion of the first link member 4 of each of the leg links 2. A
drive crank arm 9b on an output shaft of the speed reducer 9a is
connected with a driven crank arm 6a secured to the second link
member 6 coaxially with a joint shaft 5a of the knee joint 5
through the intermediary of a connection link 9c. With this
arrangement, the motive power output from the drive source 9
through the intermediary of the speed reducer 9a is transferred to
the second link member 6 through the intermediary of the connection
link 9c. Then, the second link member 6 swings about the joint
shaft 5a relative to the first link member 4, causing the leg link
2 to bend or stretch.
[0029] Each of the ground contact members 8 has a shoe 8a and a
connection member 8b, which is secured to the shoe 8a and which
extends upward. Further, the second link member 6 of the leg link 2
is connected to the connection member 8b through the intermediary
of a three-axis third joint 7. As illustrated in FIG. 1, a pair of
front and rear pressure sensors 10 and 10 for detecting load acting
on a metatarsophalangeal joint (MP joint) portion and a heel
portion of a foot of the user P is installed on the bottom surface
of an insole 8c provided in the shoe 8a. In addition, a two-axis
force sensor (not shown) is built in the ankle joint 7. The support
frame 1b of the seating member 1 incorporates a controller 12,
which is a control means, while the first link member 4
incorporates a battery 13.
[0030] The detection signals of the pressure sensors 10 and the
force sensor are input to the controller 12. Then, the controller
12 controls the drive source 9 on the basis of the signals from
these pressure sensors 10 and the force sensor to drive the knee
joint 5, thereby executing the walking assistance control for
generating the aforesaid load support force.
[0031] Here, the load support force acts on a line which connects
the support point of the longitudinal swing of the leg link 2 at
the hip joint 3 and the support point of the longitudinal swing of
the leg link 2 at the ankle joint 7, as observed from a lateral
direction (hereinafter referred 2C to as "the reference line").
Therefore, in the walking assistance control, an actual load
support force acting on the reference line (to be precise, the
resultant force of a load support force and the force from the
weights of the seating member 1 and the leg links 2) is calculated
on the basis of the detection values of the forces in the
directions of two axes detected by the force sensor. Further, based
on the detected pressures of the pressure sensors 1) of each of the
ground contact members 8, the ratio of the acting load of each foot
in relation to the total load acting on both feet of the user P is
calculated. Subsequently, a value obtained by multiplying a set
value of a load support force, which is set beforehand, by the
ratio of the load of each foot is calculated as a control target
value of the load support force to be generated at each of tee leg
links 2. Then, the drive source 9 is controlled such that the
actual load support force calculated on the basis of the detection
values of the force sensor agrees with the control target
value.
[0032] In the case where the ankle joint 7 is constituted of a turn
shaft enabling the ground contact member 8 to turn relative to the
leg link 2, a longitudinal rotation shaft member, which is
rotatable in the longitudinal direction, and a lateral rotation
shaft member, which is rotational in the lateral direction, wherein
the shaft which rotates an ankle to allow a foot of a user to turn
outward and inward in an upright posture state in which the walking
assistance device is standing with both ground contact assemblies
in contact with a ground surface or a floor surface or the like is
defined as the turn shaft, the shaft whish rotates an ankle to move
up or down a tiptoe of a foot of the user in the upright posture
state is defined as the longitudinal rotation shaft, and the shaft
which turns a foot of the user in the upright posture state in the
lateral direction, using the ankle as a support point, is defined
as the lateral rotation shaft, and if the lateral rotation shaft
member, the turn shaft member, and the longitudinal rotation shaft
member are disposed in this order beginning at the top, then the
lateral rotation axial line of the lateral rotation shaft member
and the longitudinal rotation axial line of the longitudinal
rotation shaft member gradually approach a parallel state as the
turn shaft member rotates. This leads to a danger in that foot
motions of the user cannot be properly followed, causing the user
to feel discomfort.
[0033] Moreover, if the lateral rotation shaft member and the
longitudinal rotation shaft member reach a parallel state as the
turn shaft member rotates, then the lateral rotation shaft member,
which is in the topmost position, will become a fourth joint, which
cannot be controlled by the drive source. This may cause the turn
shaft member, which disposed between the lateral rotation shaft
member and the longitudinal rotation shaft member, to easily wobble
and become unstable, making it impossible to generate a proper load
support force.
[0034] To avoid the aforesaid problem, in the ankle joint 7 of the
walking assistance device according to the first embodiment, a turn
shaft member 71, a lateral rotation shaft member 72, and a
longitudinal rotation shaft member 73 are disposed in this order
beginning at the top, as illustrated in FIG. 3 and FIG. 4. Although
FIG. 3 illustrates only the ankle joint 7 on the right side, the
ankle joint 7 on the left side is constituted in the same manner,
the right and left ankle joints 7 and 7 being laterally
symmetrical. The right and left ankle joints 7 and 7 would be
illustrated identically, so that FIG. 4 illustrates only one of
them.
[0035] The upper end of the turn shaft member 71 is rotatably
supported in a through hole 6b which is drilled at the lower end of
the second link member and which vertically penetrates. A lower end
portion of the turn shaft member 71 is provided with a through hole
71a, which penetrates in the longitudinal direction, the lateral
rotation shaft member 72 being rotationally inserted in the through
hole 71a. The lateral rotation shaft member 72 and the longitudinal
rotation shaft member 73 are connected by a connection member 74.
The upper end portion of the connection member 74 is bifurcate, and
the bifurcate upper end portion longitudinally holds the lower end
portion of the tarn shaft member 71. The bifurcate portion of the
connection member 74 is provided with a through hole 74a, which
longitudinally penetrates to match the through hole 71a of the turn
shaft member 71, the lateral rotation shaft member 72 being
rotatably supported in the through hole 74a. The lower end portion
of the connection member 74 is provided with a through hole 74b
penetrating in the lateral direction, and the longitudinal rotation
shaft member 73 being rotatably supported in the through hole
74b.
[0036] With the arrangement described above, the ankle joint 7
maintains a state, wherein the lateral rotation shaft member 72 and
the longitudinal rotation shaft member 73 are always orthogonal to
each other, regardless of the rotation of the turn shaft member 71,
allowing the foot motions of the user to be properly followed. This
makes it possible to protect the user from feeling discomfort.
Further, the lateral rotation axial line of the lateral rotation
shaft member 72 and the longitudinal rotation axial line of the
longitudinal rotation shaft member 73 will not become parallel,
thus making it possible to obviate the state wherein the fourth
joint that cannot be controlled by the drive source develops, as in
the case where the turn shaft member is disposed between the
lateral rotation shaft member and the longitudinal rotation shaft
member. Hence, an appropriate load support force can be always
generated.
[0037] The turn shaft member 71 may alternatively be disposed at
the bottommost position and connected to the ground contact member
8. Further, the lateral rotation shaft member 72 and the
longitudinal rotation shaft member 73 may be vertically switched
and the lateral rotation shaft member 72 may be connected to the
ground contact member 8.
[0038] Referring now to FIG. 5 through FIG. 7, a walking assistance
device to which a second embodiment of the ankle joint structure in
accordance with the present invention has been applied will be
described. As illustrated in FIG. 5 and FIG. 6, the walking
assistance device according to the second embodiment is exactly the
same as the first embodiment except for the construction of an
ankle joint 7.
[0039] The ankle joint 7 of the second embodiment has a spherical
joint 75. Here, the spherical joint in its discrete form has three
degrees of freedom. This is advantageous for achieving compactness,
while presenting a problem in that operating angles are small,
making it impossible to properly follow the foot motions of the
user.
[0040] Hence, as illustrated in FIG. 7, the ankle joint 7 of the
second embodiment is provided with a turn shaft member 71 having
its upper end turnably connected to a leg link 2, in addition to
the spherical joint 75. A retaining hole 71b laterally penetrating
is formed in the lower end portion of the turn shaft member 71, the
retaining hole 71b swingably retains a sphere 75a of the spherical
joint 75, and a joint shaft member 75b of the spherical joint 75 is
connected to the ground contact member 8. Although FIG. 7
illustrates only the ankle joint 7 on the right side, the ankle
joint 7 on the left side is constituted in the same manner, the
right and left ankle joints 7 being laterally symmetrical.
[0041] Thus, the turn shaft member 71 ensures the rotation of a
foot in a turning direction, which is larger than a lateral
rotation and a longitudinal rotation of a foot of the user, while
the spherical joint 75 ensures the lateral rotation and the
longitudinal rotation, which are relatively smaller than the
rotation of a foot in the turning direction. This arrangement makes
it possible to configure the ankle joint 7 capable of following the
foot motions of a user so properly and smoothly that the user does
not feel uncomfortable.
[0042] The joint shaft member 75b of the spherical joint 75 is
constructed such that an inner end portion thereof connected to the
ground contact member 8 is positioned below an outer end portion of
the joint shaft member 75b. Foot motions of a human being in many
cases cause the leg link 2 to incline inward from an upright state,
as observed from the front, when, for example, the user opens
his/her legs apart, and an angle formed by the leg link 2 inclining
outward is not so large, as observed from the front. Hence, in the
upright posture state, tilting the joint shaft member 75b such that
the inner end portion thereof is positioned below the outer end
portion thereof enables the leg link 2 to take a large angle
(operating angle) when tilting inward relative to the ground
contact member 8, thus making it easy to further properly follow
the foot motions of the user.
[0043] Alternatively, the turn shaft member 71 may be connected to
the ground contact member 8 and the spherical joint 75 may be
connected to the leg link 2. In this case, the joint shaft member
75b of the spherical joint 75 may be constructed such that the
inner end portion thereof is positioned above the outer end portion
thereof. This enables the user to open his/her legs wide apart,
making it possible to further properly follow the foot motions of
the user.
* * * * *